Coughs, fevers and green mucus can accompany an infection, but most of the time, doctors can only guess whether the culprit is bacterial or viral. A new study points out a way to identify the perp.
An infection changes the behavior of the afflicted person’s genes, and that host response
differs depending on whether bacteria or a virus is doing the damage, scientists report in the Dec. 15
Immunity. This virus-bacteria distinction could ultimately help doctors quickly figure out what ails a person, and whether antibiotics, antiviral drugs or just chicken soup and sleep is the best treatment.
To find the viral fingerprints, computational immunologist Purvesh Khatri of Stanford University and colleagues combed through a wide variety of publicly available datasets that included information about how human genes behaved after an infection of influenza, human rhinovirus and respiratory syncytial virus, or RSV. The researchers churned these diverse datasets through a series of sophisticated mathematical analyses, a process that ultimately pinpointed a consistent viral calling card — a list of nearly 400 genes, each of which grew either more or less active during a viral attack. Many of those genes make proteins known to be involved in virus responses and inflammation.
Khatri and colleagues then tested whether the behavior of these genes could distinguish viral infections from bacterial infections, or no infection at all. Looking at separate datasets that weren’t used to generate the gene list, the researchers found that the virus signature could predict whether a person was infected with a virus, ruling out a bacterial cause. “This was a very robust host response,” Khatri says.
That response is “the most solid signature people have found,” says systems immunologist Shai Shen-Orr of Technion-Israel Institute of Technology in Haifa. And because the signature was consistent across a wide array of studies, the results have added heft. “It’s like this has just been lying here, waiting for someone to pick up,” he says. “The signal just jumped out.” ....
